On a budget, skip Aquarium Barcelona — the spend outweighs the payoff.
€€€ (~€25)
The 80-metre acrylic tunnel with sharks and rays gliding overhead is the genuine wow, and the Mediterranean focus gives it a faint local hook other city aquariums lack. Honest verdict: this is a utility entry, not a taste one. It earns its keep on a wet afternoon with small children or as a pre/post-beach add-on, and very little else — adults without kids will find it overpriced for its modest size, and the tanks can feel cramped versus its ticket.